Hydrogen

Hydrogen is the first chemical element in the periodic table, with atomic number 1, a symbol (H) and is studied to be the most abundant and lightest element in the Universe. It comprises approximately 75% of elemental mass in the Universe. It's known that, this same element is quite rare on earth. Read more on this page about Hydrogen.

It is ironic how the discovery of the simplest element known to man turned out to be so complicated. Although the credit goes to a number of alchemists and physicists, it was a long time before someone managed to classify the true...

Most of the "EXIT" sign boards displayed in buildings, theaters, skyscrapers, shops, and other places, are made from a self-luminous tritium source. This article provides some more information about these sign boards.